CloudWatch: Added missing Cassandra metrics

[ilyastoli]

What this PR does / why we need it:
Adding CloudWatch Cassandra metrics that were missing in PR #23299
Which issue(s) this PR fixes:
Fixes #23260

Special notes for your reviewer:
Those metrics are missing in the AWS Cassandra monitoring documentation yet they are available to use

aws cloudwatch list-metrics --namespace "AWS/Cassandra" --output json | grep MetricName | sort | uniq
            "MetricName": "AccountMaxReads",
            "MetricName": "AccountMaxTableLevelReads",
            "MetricName": "AccountMaxTableLevelWrites",
            "MetricName": "AccountMaxWrites",
            "MetricName": "AccountProvisionedReadCapacityUtilization",
            "MetricName": "AccountProvisionedWriteCapacityUtilization",
            "MetricName": "ConsumedReadCapacityUnits",
            "MetricName": "ConsumedWriteCapacityUnits",
            "MetricName": "MaxProvisionedTableReadCapacityUtilization",
            "MetricName": "MaxProvisionedTableWriteCapacityUtilization",
            "MetricName": "ReturnedItemCountBySelect",
            "MetricName": "SuccessfulRequestCount",
            "MetricName": "SuccessfulRequestLatency",
            "MetricName": "UserErrors",

[CLAassistant]

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[papagian]

LGTM

Thank you for contributing!